(1) Field of the Invention:
The present invention relates to an improvement in the photosensitive layer for electrophotography. More particularly, the present invention relates to a photosensitive layer containing a polyvinyl carbazole type photoconductor in which mechanical properties such as abrasion resistance, toughness and adhesion are improved.
(2) Description of the Prior Art:
Polyvinyl carbazole (often referred to as "PVK" hereinafter) is widely used as a polymeric photoconductor having film-forming and bonding properties for the manufacture of photosensitive materials for electrophotography. However, PVK is defective in that the toughness and adhesion are insufficient. For example, PVK is brittle, readily wears away while used for a long time and is apt to separate from a substrate in the form of slices.
As means for overcoming these defects of PVK, there is ordinarily adopted a method in which a polymeric binder such as a polyester resin, an epoxy resin or a polycarbonate resin is incorporated into PVK. However, these polymeric binders have no photoconductivity at all, and if such non-photoconductive binder is incorporated, a disadvantage of reduction of the sensitivity of the obtained photosensitive layer cannot be avoided. Furthermore, these polymeric binders are ordinarily poor in the compatibility with PVK, and therefore, a photosensitive layer comprising a blend of PVK and such polymeric binder is likely to have a heterogeneous structure and the resulting photosensitive layer is still insufficient in electrophotographic properties.